EP1185426A1 - Coreless bead for tyre - Google Patents

Coreless bead for tyre

Info

Publication number
EP1185426A1
EP1185426A1 EP00935005A EP00935005A EP1185426A1 EP 1185426 A1 EP1185426 A1 EP 1185426A1 EP 00935005 A EP00935005 A EP 00935005A EP 00935005 A EP00935005 A EP 00935005A EP 1185426 A1 EP1185426 A1 EP 1185426A1
Authority
EP
European Patent Office
Prior art keywords
carcass reinforcement
bead
radially
axially
tire according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP00935005A
Other languages
German (de)
French (fr)
Other versions
EP1185426B1 (en
Inventor
Pierre Durif
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Michelin Recherche et Technique SA Switzerland
Michelin Recherche et Technique SA France
Societe de Technologie Michelin SAS
Original Assignee
Michelin Recherche et Technique SA Switzerland
Michelin Recherche et Technique SA France
Societe de Technologie Michelin SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Michelin Recherche et Technique SA Switzerland, Michelin Recherche et Technique SA France, Societe de Technologie Michelin SAS filed Critical Michelin Recherche et Technique SA Switzerland
Publication of EP1185426A1 publication Critical patent/EP1185426A1/en
Application granted granted Critical
Publication of EP1185426B1 publication Critical patent/EP1185426B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
    • B60C15/0009—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion
    • B60C15/0018—Tyre beads, e.g. ply turn-up or overlap features of the carcass terminal portion not folded around the bead core, e.g. floating or down ply
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
    • B60C15/02—Seating or securing beads on rims
    • B60C15/0203—Seating or securing beads on rims using axially extending bead seating, i.e. the bead and the lower sidewall portion extend in the axial direction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
    • B60C15/02—Seating or securing beads on rims
    • B60C15/024—Bead contour, e.g. lips, grooves, or ribs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
    • B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T152/00—Resilient tires and wheels
    • Y10T152/10—Tires, resilient
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T152/00—Resilient tires and wheels
    • Y10T152/10—Tires, resilient
    • Y10T152/10495—Pneumatic tire or inner tube
    • Y10T152/10819—Characterized by the structure of the bead portion of the tire
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T152/00—Resilient tires and wheels
    • Y10T152/10—Tires, resilient
    • Y10T152/10495—Pneumatic tire or inner tube
    • Y10T152/10819—Characterized by the structure of the bead portion of the tire
    • Y10T152/10828—Chafer or sealing strips

Definitions

  • the invention relates to a tire comprising at least one tread joined to two beads by means of two sidewalls and a carcass reinforcement, said tire being able to be used with or without an independent inner tube and intended, after mounting on a rim standard and inflation, to the equipment of any vehicle likely to roll.
  • PCT application EP 98/06 832 filed on October 28, 1998 describes and claims a tire, intended to be mounted on a rim of axial width L, with rim seats making with the axis of rotation an angle ⁇ such as 0 ° ⁇ ⁇ 16 °, and rim flanges with rounded hooks.
  • Said tire comprises a tread joined to two beads by two sidewalls and at least one carcass reinforcement formed of at least one ply of reinforcing elements, each bead being devoid of bead wire and said carcass reinforcement having in each bead a curved meridian profile going axially and radially from the outside to the inside, to form an axially inside edge located at an angle ⁇ open axially and radially inward, one side of which is parallel to the axis of rotation, and of value at most equal to 25 °.
  • Said carcass reinforcement is in each bead, at least radially on the outside and axially on the inside, reinforced by at least one first continuous additional layer, of meridian profile substantially parallel to the meridian profile of said carcass reinforcement in the bead and comprising at least a first part composed of at least one ply formed of inextensible reinforcing elements making with the circumferential direction an angle between - 2.5 ° and + 2.5 °, the radially upper end of said additional ply being distant from the axis of rotation by an amount at least equal to 0.96 times the distance separating from said axis the point of the corresponding flange of the mounting rim most distant from said axis of rotation, and the axially inner end being distant from the equatorial plane by an amount at most equal to 0.43 times the width L of the mounting rim.
  • the first additional layer may be formed from two parts of several additional plies of inextensible reinforcing elements, superimposed on each other and whose lengths may be equal or not.
  • Another additional reinforcement layer continuous and arranged radially inside and axially outside, has proven to be very advantageous.
  • Said layers are, essentially, formed of inextensible cables, preferably metallic, and forming with the circumferential direction an angle comprised between - 2.5 ° and + 2.5 °.
  • Such structures although making it possible to solve the problems posed, do not have sufficient endurance, due to the appearance and propagation of carcass reinforcement ruptures due to the variation in curvature of the meridian profile of said reinforcement during rolling, variation between the curvature when the meridian considered passes through the contact ellipse and when it is opposite to said ellipse.
  • the tire in accordance with the invention, intended to be mounted on a rim whose seats form with the axis of rotation an angle ⁇ such that 0 ° ⁇ ⁇ 16 °, and the rim flanges of which have rounded hooks, comprising a tread joined in two beads (3) by two sides (2) and at least one carcass reinforcement (1) formed of at least one ply of reinforcing elements, is characterized in that each bead (3) is devoid of rod, said reinforcement carcass (1) having in each bead (3) a meridian profile curved going axially and radially from the outside to the inside to form an axially inner edge located at an angle ⁇ open axially and radially inward, of which one of the sides is parallel to the axis of rotation, and of value at most equal to 25 °, said carcass reinforcement (1) being in each bead (3) at least radially on the outside and axially on the reinforced interior, on the one hand by at least one first additional continuous layer (6)
  • rim flange seen in meridian section, is understood the assembly formed by the part substantially perpendicular to the axis of rotation extended on the one hand, radially on the outside, by a circular part, forming what is called sometimes the rim hook, and on the other hand, radially inside, by the arc of a circle connecting the axially outer end of the rim seat to said assembly.
  • meridian profile of a carcass reinforcement in a bead is meant the meridian profile of the geometrically mean fiber of said reinforcement, seen in meridian section, said profile being considered radially inside a straight line parallel to the axis of rotation of the mounting rim and of the tire passing through the point of the rim hook, corresponding to the bead considered, the furthest from the axis of rotation.
  • inextensible reinforcing element is meant a cable or a monofilament, having under a force of 20% of the breaking force a relative elongation at most equal to 1.5%.
  • the first and second additional layers will preferably be formed of metallic cables or monofilaments, and preferably of steel, in the case of tires of the "Heavy-duty” or “Civil Engineering” type, but may advantageously be formed of textile elements, preferably in aromatic polyamide, in the case of tires for airplanes, agricultural tractors or for passenger cars for example
  • the endurance of the tire will be further improved if the thickness of rubber, existing between the average fiber of the meridian profile of the carcass reinforcement and the external wall of the bead, is, over the contact length between bead and rim reduced by the contact length between the bead and rim seats respectively, at least equal to 0.02% of the maximum axial width of the carcass reinforcement.
  • the meridian profile of the assembly formed by the carcass reinforcement and the additional layers a profile very closely linked to the profile of the carcass reinforcement, will be, in a bead, advantageously adapted to the meridian profile of the rim on which said bead will be mounted.
  • the meridian profile of the additional plies differs, in fact, from the meridian profile of the carcass reinforcement only by the possible variation of the rubber layer (s) of decoupling, reinforced or not, existing (s) between the two frames, which explains why the said profiles are said to be substantially parallel.
  • the meridian profile of the second additional layer may be strictly parallel to the carcass reinforcement profile, a single layer of rubber of constant thickness separating the two profiles.
  • the meridian profile of the second layer may be substantially parallel to the carcass reinforcement profile, one or more plies of the first additional layer being able to be inserted radially between the carcass reinforcement and the second additional layer, while the ) remaining ply (s) of the first layer are radially outside and axially inside the second additional layer.
  • Said carcass reinforcement meridian profile in a bead can be formed, going radially and axially inwards, possibly with a first concave arc of a circle extended tangentially by a second convex arc of circle, said second arc of circle being possibly extended tangentially by a line segment.
  • the radially outer end of the first concave arc is on the one hand radially distant from the axis of rotation by an amount equal to the radius of the circle at the geometrical location of the points of the rim flange furthest from said axis, and on the other hand axially distant from the equatorial plane by an amount between L + 0.1 L and L - 0.1 L.
  • Said radially outer end is also the point of tangency with the convex meridian profile of the carcass reinforcement in the flank.
  • the center of curvature of the first arc has, with respect to the two axes that are the trace of the equatorial plane and the axis of rotation, the same coordinates than the center of curvature of the rim hook.
  • the length of said first arc of a carcass reinforcement profile it is at least zero, the meridian profile of carcass reinforcement in the bead starting directly with the second convex arc, and at most equal to the length an arc of a circle whose radially lower end would be the point of tangency of said arc with a perpendicular to the axis of rotation.
  • Said first arc of a circle is tangentially extended radially and axially inside by a second arc of a circle with a radius of curvature which can be between a minimum value of 5 mm and a maximum value equal to the radius of curvature of the meridian profile of reinforcement carcass in the sidewall measured at the point of tangency between said profile and the first arc, said maximum value being the value of radius preferably used when the first arc has a zero length.
  • the second arc of a circle is optionally tangentially extended radially and axially inside by a straight line segment, the axially inner end of which is also the end of the meridian profile of the carcass reinforcement.
  • the axially inner edge of the meridian profile is composed either of a part of the second arc of a circle to which the line segment is added, or of a part of an arc of a circle.
  • Said edge is the part of the meridian profile located at an angle defined by a half-line tangent to the second arc of a circle and making with the axis of rotation an angle of 25 ° and a half-line parallel to said axis of rotation, the origin is precisely the point of tangency of the second arc of a circle with the half-line oriented at 25 °.
  • the first additional layer has an axially inner end which may be closer or further away from the equatorial plane than the axially inner end of the carcass reinforcement.
  • the first additional layer can be separated from the second additional layer by a small thickness of rubber mixture, sum of the two respective thicknesses of the calendering layers of the two adjacent plies, while between said apex and the radially upper end, said thickness is between 1.0 and 1.8 times the thickness mentioned above.
  • the second additional layer its axially inner end is axially distant from the equatorial plane by an amount substantially equal to the axial distance separating the axially inner end of the carcass reinforcement in the bead.
  • said second additional layer is advantageously separated from the carcass reinforcement and / or from the first additional layer by a thickness which is the sum of the two thicknesses of the calendering layers of the adjacent layers.
  • a third additional continuous reinforcement layer can also prove to be very advantageous.
  • Said third layer axially outside and radially inside at least the radially innermost and axially outermost ply of the carcass reinforcement, also has a meridian profile substantially parallel to the meridian profile of said reinforcement carcass in the bead.
  • Said layer is formed of at least one ply of reinforcing elements.
  • It can be continuous and homogeneous over its entire length from its radially upper end which can be located radially outside, but preferably radially inside, from the straight line parallel to the axis of rotation of the rim and passing through the point of the rim flange, corresponding to the bead considered, the furthest from the axis of rotation, up to its axially inner end and closest to the equatorial plane. It is then advantageously formed of inextensible cables, preferably metallic, and making with the circumferential direction an angle between - 2.5 ° and + 2.5 °.
  • said third additional layer may also be non-homogeneous over its width although continuous, and it is then advantageously formed of two parts: a first part lying between its radially upper end and a point situated between the middle of the second arc of a circle of the meridian profile of carcass reinforcement in the bead and the apex of the angle ⁇ in which the carcass reinforcement edge is situated, and a second part, extending axially inside and radially inside the first part and lying between said point and its radially lower end and axially closest to the equatorial plane.
  • the first part is formed of at least one ply of inextensible cables, preferably metallic in steel, and forming with the circumferential direction an angle between - 2.5 ° and + 2.5 °
  • the second part is advantageously formed of at least one ply of reinforcing elements, said ply having the properties of being very slightly compressible in the transverse direction and advantageously extensible in the circumferential direction, which, on the one hand, allows simple and reproducible control pressures exerted by the bead seat on the rim seat, the inventors having unexpectedly found that said pressures were a function of the tensile strength of the reinforcing elements constituting the ply (s) of the second part of the second additional layer, and on the other hand, facilitates the laying in manufacturing of said additional layer.
  • Said second part may advantageously be formed from at least one ply:
  • each element having a circumferential length which can be between 0.1 times and 1 time the circumferential length of the ply and the spaces between elements being offset meridally with respect to spaces of the axially adjacent rows and said elements or rows of elements being however in this case parallel to each other and practically contiguous in the transverse direction,
  • the laying of the second part of the second layer can be further facilitated if the ply (s) of said part are formed from strips of a few circumferential reinforcing elements, circumferentially discontinuous strips, the spaces of discontinuity between strips doing with the circumferential direction an angle different from the angle made with the same direction by the carcass reinforcement reinforcing elements, the difference being at least equal to 10 °.
  • the position of the third layer and of the plies which compose it can be a function of the number of plies making up the carcass reinforcement of the tire. If said carcass reinforcement is formed of at most three plies, the third additional layer is preferably entirely located axially outside and radially inside the carcass ply radially innermost and axially most outside the carcass reinforcement. On the other hand, if said carcass reinforcement is formed of at least four plies, the plies which form the third additional layer are preferably such that two of them enclose a group of carcass plies which can be formed of one or more plies of carcass reinforcement.
  • the "Heavy Duty" tire of dimension 385/65 R 22.5 (FIG. 1), intended to be mounted on a rim with a hollow base having rim seats inclined at 15 °, comprises a tread joined to two beads (3 ) by two sides (2).
  • a carcass reinforcement composed of a single ply (1) of radial metallic steel cables, reinforces said tire and is surmounted by a crown reinforcement (not shown) formed by at least two plies of parallel metallic steel cables between them in each tablecloth and crossed a tablecloth to the next, making angles between 10 ° and 35 ° with the circumferential direction.
  • the meridian profile of the geometrically medium fiber of the carcass ply (1), seen in meridian section, said profile being considered radially inside a straight line XX 'parallel to the axis of rotation of the mounting rim and the tire passing through the point of the rim flange, corresponding to the bead considered, the furthest from the axis of rotation, is constituted by a first concave arc AB.
  • Point A is distant from the equatorial plane by an amount equal to 149 mm, i.e. 0.5 times the width L already 11.75 on which the tire will be mounted, while point D is distant from the same plane by an amount equal to 0.3 times the same rim width.
  • the arc of a circle AB does not, due to the particular shape of the meridian profile of the flange of the rim with seats 15 °, the maximum possible length, point B n ' not being a point of tangency with a straight line perpendicular to the axis of rotation.
  • Said meridian profile is therefore curved going axially and radially from the outside to the inside to form an axially inner SD edge, located in an angle ⁇ open axially and radially inwards, one of the sides of which forms with the axis of rotation an angle of 25 °, is tangent to the second arc of a circle BC in S, and the other side of which starting from S is parallel to said axis of rotation.
  • the first additional radially outer and axially inner layer (6) is composed of three plies (6 ⁇ , (6 2 ) and (6 3 ) of metallic steel cables 68x23 circumferentially oriented and whose breaking force is at least equal to 700 daN.
  • the radially lower ends of the three plies are further from the equatorial plane than the end of the carcass ply and the radially upper ends radially stepped are radially inside the line XX ', with the exception of the ply (6j ) closest to the carcass ply (1).
  • a second additional layer (7) consisting of a single ply (7), in the example described, of 19x18 steel wire cables oriented radially.
  • the radially upper end of said ply (7) is located radially largely above the line XX 'to be located approximately between said line and the line of greatest axial width of the carcass reinforcement (1).
  • the axially inner end it is located at an axial distance from the equatorial plane equal to the axial distance separating from said plane the end of the carcass ply (1).
  • the additional ply (6 is decoupled from the second additional layer (7) by a thin layer of rubber mixture (8) whose thickness is equal to the sum of the two thicknesses of calendering mixture respectively covering the cables of said additional plies, and in the case described equal to 0.6 mm. It is the same for the separation between the second additional layer (7) and the carcass reinforcement (1), decoupled from one another by the thick rubber (8) equal to 1.2 mm.
  • the third additional layer (9) is made up of two parts:
  • a second part (91) formed of a ply of metallic steel cables corrugated in the plane of the ply and of circumferential mean orientation and with a ratio a / ⁇ d ripple amplitude a over the wavelength ⁇ between 0.03 and 0.1, the said steel cables being of smaller diameter than that of the cables of the first part (90), since equal to 1 , 4 mm.
  • the thickness e of rubber between the average fiber of the carcass ply (1) and the external wall of the bead is, over a length equal to the total length of contact between said external wall of the bead and the internal wall of the mounting rim, reduced by the common length of the bead and rim seats respectively, equal to 13 mm, that is to say at least equal to 0.034% the maximum axial width of the carcass reinforcement (1).
  • the length considered corresponds substantially to the length AS of the meridian profile of the carcass reinforcement (1).
  • the entire bead is completed by one (or more) rubber fillings (4) axially inside and radially outside the additional layer (6).

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Tires In General (AREA)

Abstract

The invention concerns a tyre designed to be mounted on a rim whereof the edges comprise round-shaped rim attachments, including at least two beads (3) and a reinforced casing (1) formed by at least one ply of reinforcing elements. Each bead (3) is coreless and said reinforced casing (1) has in each bead (3) a curved meridian profile viewed axially and radially inwards from outwards to form an axially inner ridge located in an angle alpha opening axially and radially inwards, said reinforced casing (1) being in each bead (3) reinforced at least radially outward and axially inward, by at least a first additional continuous layer (6), formed with inextensible circumferential reinforcing elements, and by at least a second continuous additional layer (7), formed with inextensible radial reinforcing elements, the two additional layers having profiles substantially parallel to the meridian profile of the reinforced casing in the bead.

Description

Bourrelet sans tringle pour pneumatiqueTire bead without bead
L'invention concerne un pneumatique comprenant au moins une bande de roulement réunie à deux bourrelets par l'intermédiaire de deux flancs et une armature de carcasse, ledit pneumatique pouvant être utilisé avec ou sans chambre à air indépendante et destiné, après montage sur une jante normalisée et gonflage, à l'équipement de tout véhicule susceptible de rouler.The invention relates to a tire comprising at least one tread joined to two beads by means of two sidewalls and a carcass reinforcement, said tire being able to be used with or without an independent inner tube and intended, after mounting on a rim standard and inflation, to the equipment of any vehicle likely to roll.
La demande PCT EP 98/06 832 déposée le 28 octobre 1998 décrit et revendique un pneumatique, destiné à être monté sur une jante de largeur axiale L, avec des sièges dé jante faisant avec l'axe de rotation un angle γ tel que 0° < γ < 16°, et des rebords de jante avec crochets arrondis. Ledit pneumatique comprend une bande de roulement réunie à deux bourrelets par deux flancs et au moins une armature de carcasse formée d'au moins une nappe d'éléments de renforcement, chaque bourrelet étant dépourvu de tringle et ladite armature de carcasse ayant dans chaque bourrelet un profil méridien courbé en allant axialement et radialement de l'extérieur à l'intérieur, pour former un bord axialement intérieur localisé dans un angle α ouvert axialement et radialement vers l'intérieur, dont l'un des côtés est parallèle à l'axe de rotation, et de valeur au plus égale à 25°. Ladite armature de carcasse est dans chaque bourrelet, au moins radialement à l'extérieur et axialement à l'intérieur, renforcée par au moins une première couche additionnelle continue, de profil méridien sensiblement parallèle au profil méridien de ladite armature de carcasse dans le bourrelet et comportant au moins une première partie composée d'au moins une nappe formée d'éléments de renforcement inextensibles faisant avec la direction circonférentielle un angle compris entre - 2,5° et + 2,5°, l'extrémité radialement supérieure de ladite nappe additionnelle étant distante de l'axe de rotation d'une quantité au moins égale à 0,96 fois la distance séparant dudit axe le point du rebord correspondant de la jante de montage le plus éloigné dudit axe de rotation, et l'extrémité axialement intérieure étant distante du plan équatorial d'une quantité au plus égale à 0,43 fois la largeur L de la jante de montage. II est alors possible de mieux maîtriser la répartition des pressions de contact entre la jante et le pneumatique, au niveau des sièges respectifs de jante et de bourrelet tout en permettant l'amélioration de la résistance au déroulement d'armature de carcasse dans le cas d'échauffement élevé des bourrelets, sans utiliser de tringles d'ancrage de l'armature de carcasse.PCT application EP 98/06 832 filed on October 28, 1998 describes and claims a tire, intended to be mounted on a rim of axial width L, with rim seats making with the axis of rotation an angle γ such as 0 ° <γ <16 °, and rim flanges with rounded hooks. Said tire comprises a tread joined to two beads by two sidewalls and at least one carcass reinforcement formed of at least one ply of reinforcing elements, each bead being devoid of bead wire and said carcass reinforcement having in each bead a curved meridian profile going axially and radially from the outside to the inside, to form an axially inside edge located at an angle α open axially and radially inward, one side of which is parallel to the axis of rotation, and of value at most equal to 25 °. Said carcass reinforcement is in each bead, at least radially on the outside and axially on the inside, reinforced by at least one first continuous additional layer, of meridian profile substantially parallel to the meridian profile of said carcass reinforcement in the bead and comprising at least a first part composed of at least one ply formed of inextensible reinforcing elements making with the circumferential direction an angle between - 2.5 ° and + 2.5 °, the radially upper end of said additional ply being distant from the axis of rotation by an amount at least equal to 0.96 times the distance separating from said axis the point of the corresponding flange of the mounting rim most distant from said axis of rotation, and the axially inner end being distant from the equatorial plane by an amount at most equal to 0.43 times the width L of the mounting rim. It is then possible to better control the distribution of the contact pressures between the rim and the tire, at the level of the respective rim and bead seats while allowing the improvement of the resistance to unwinding of carcass reinforcement in the case of '' high heating of the beads, without using rods for anchoring the carcass reinforcement.
Dans le cas de pneumatiques dont la pression de gonflage recommandée est élevée, le document cité mentionne que la première couche additionnelle peut être formée de deux parties de plusieurs nappes additionnelles d'éléments de renforcements inextensibles, superposées les unes aux autres et dont les longueurs pourront être égales ou non. La présence d'une autre couche additionnelle de renforcement, continue et disposée radialement à l'intérieur et axialement à l'extérieur, s'est avérée très avantageuse. Les dites couches sont, pour l'essentiel, formées de câbles inextensibles, de préférence métalliques, et faisant avec la direction circonférentielle un angle compris entre - 2,5° et + 2,5°.In the case of tires whose recommended inflation pressure is high, the cited document mentions that the first additional layer may be formed from two parts of several additional plies of inextensible reinforcing elements, superimposed on each other and whose lengths may be equal or not. The presence of another additional reinforcement layer, continuous and arranged radially inside and axially outside, has proven to be very advantageous. Said layers are, essentially, formed of inextensible cables, preferably metallic, and forming with the circumferential direction an angle comprised between - 2.5 ° and + 2.5 °.
De telles structures, bien que permettant de résoudre les problèmes posés, ne présentent pas une endurance suffisante, du fait de l'apparition et la propagation de ruptures d'armature de carcasse dues à la variation de courbure du profil méridien de ladite armature au cours du roulage, variation entre la courbure lorsque le méridien considéré passe dans l'ellipse de contact et lorsqu'il est à l'opposé de ladite ellipse.Such structures, although making it possible to solve the problems posed, do not have sufficient endurance, due to the appearance and propagation of carcass reinforcement ruptures due to the variation in curvature of the meridian profile of said reinforcement during rolling, variation between the curvature when the meridian considered passes through the contact ellipse and when it is opposite to said ellipse.
Afin de remédier aux dits problèmes d'endurance, le pneumatique, conforme à l'invention, destiné à être monté sur une jante dont les sièges font avec l'axe de rotation un angle γ tel que 0° < γ < 16°, et dont les rebords de jante ont des crochets arrondis, comprenant une bande de roulement réunie à deux bourrelets (3) par deux flancs (2) et au moins une armature de carcasse (1 ) formée d'au moins une nappe d'éléments de renforcement, est caractérisé en ce que chaque bourrelet (3) est dépourvu de tringle, ladite armature de carcasse (1) ayant dans chaque bourrelet (3) un profil méridien courbé en allant axialement et radialement de l'extérieur à l'intérieur pour former un bord axialement intérieur localisé dans un angle α ouvert axialement et radialement vers l'intérieur, dont l'un des côtés est parallèle à l'axe de rotation, et de valeur au plus égale à 25°, ladite armature de carcasse (1) étant dans chaque bourrelet (3) au moins radialement à l'extérieur et axialement à l'intérieur renforcée, d'une part par au moins une première couche additionnelle (6) continue, composée d'au moins une nappe (61 , 62, 63) formée d'éléments de renforcement inextensibles faisant avec la direction circonférentielle un angle compris entre - 2,5° et + 2,5°, et d'autre part par au moins une deuxième couche additionnelle (7) continue, composée d'au moins une nappe formée d'éléments de renforcement inextensibles et radiaux, les deux couches additionnelles ayant des profils méridiens sensiblement parallèles au profil méridien d'armature de carcasse dans le bourrelet et les extrémités radialement supérieures des dites première et deuxième couches additionnelles étant distantes de l'axe de rotation de quantités au moins égales respectivement à 0,96 fois et 1,20 fois la distance séparant dudit axe le point du rebord correspondant de la jante de montage le plus éloigné dudit axe de rotation.In order to remedy said endurance problems, the tire, in accordance with the invention, intended to be mounted on a rim whose seats form with the axis of rotation an angle γ such that 0 ° <γ <16 °, and the rim flanges of which have rounded hooks, comprising a tread joined in two beads (3) by two sides (2) and at least one carcass reinforcement (1) formed of at least one ply of reinforcing elements, is characterized in that each bead (3) is devoid of rod, said reinforcement carcass (1) having in each bead (3) a meridian profile curved going axially and radially from the outside to the inside to form an axially inner edge located at an angle α open axially and radially inward, of which one of the sides is parallel to the axis of rotation, and of value at most equal to 25 °, said carcass reinforcement (1) being in each bead (3) at least radially on the outside and axially on the reinforced interior, on the one hand by at least one first additional continuous layer (6), composed of at least one ply (61, 62, 63) formed of inextensible reinforcing elements forming with the circumferential direction an angle between - 2.5 ° and + 2.5 °, and other part by at least one second additional continuous layer (7), composed of at least one ply formed of inextensible and radial reinforcing elements, the two additional layers having meridian profiles substantially parallel to the meridian profile of carcass reinforcement in the bead and the radially upper ends of said first and second additional layers being distant from the axis of rotation by quantities at least equal respectively to 0.96 times and 1.20 times the distance separating from said axis the point of the corresponding rim of the rim most distant from said axis of rotation.
Il faut entendre par rebord de jante, vu en section méridienne, l'ensemble formé par la partie sensiblement perpendiculaire à l'axe de rotation prolongée d'une part, radialement à l'extérieur, par une partie circulaire, formant ce qui est appelé parfois le crochet de jante, et d'autre part, radialement à l'intérieur, par l'arc de cercle de raccordement de l'extrémité axialement extérieure du siège de jante audit ensemble.By rim flange, seen in meridian section, is understood the assembly formed by the part substantially perpendicular to the axis of rotation extended on the one hand, radially on the outside, by a circular part, forming what is called sometimes the rim hook, and on the other hand, radially inside, by the arc of a circle connecting the axially outer end of the rim seat to said assembly.
Par profil méridien d'une armature de carcasse dans un bourrelet, il faut entendre le profil méridien de la fibre géométriquement moyenne de ladite armature, vue en section méridienne, ledit profil étant considéré radialement à l'intérieur d'une droite parallèle à l'axe de rotation de la jante de montage et du pneumatique passant par le point du crochet de jante, correspondant au bourrelet considéré, le plus éloigné de l'axe de rotation.By meridian profile of a carcass reinforcement in a bead, is meant the meridian profile of the geometrically mean fiber of said reinforcement, seen in meridian section, said profile being considered radially inside a straight line parallel to the axis of rotation of the mounting rim and of the tire passing through the point of the rim hook, corresponding to the bead considered, the furthest from the axis of rotation.
Il faut entendre par élément de renforcement inextensible un câble ou un monofilament, présentant sous une force de 20 % de la force de rupture un allongement relatif au plus égal à 1 ,5 %. Les première et deuxième couches additionnelles seront préférentiellement formées de câbles ou monofilaments métalliques, et de préférence en acier, dans le cas de pneumatiques de type "Poids-Lourds" ou "Génie Civil", mais pourra être avantageusement formée d'éléments textiles, de préférence en polyamide aromatique, dans le cas de pneumatiques pour Avions, Tracteurs agricoles ou pour voitures de Tourisme par exempleBy inextensible reinforcing element is meant a cable or a monofilament, having under a force of 20% of the breaking force a relative elongation at most equal to 1.5%. The first and second additional layers will preferably be formed of metallic cables or monofilaments, and preferably of steel, in the case of tires of the "Heavy-duty" or "Civil Engineering" type, but may advantageously be formed of textile elements, preferably in aromatic polyamide, in the case of tires for airplanes, agricultural tractors or for passenger cars for example
L'endurance du pneumatique sera encore améliorée si l'épaisseur de caoutchouc, existante entre la fibre moyenne du profil méridien de l'armature de carcasse et la paroi externe du bourrelet, est, sur la longueur de contact entre bourrelet et jante diminuée de la longueur de contact entre sièges respectivement de bourrelet et de jante, au moins égale à 0,02 % de la largeur axiale maximale de l'armature de carcasse.The endurance of the tire will be further improved if the thickness of rubber, existing between the average fiber of the meridian profile of the carcass reinforcement and the external wall of the bead, is, over the contact length between bead and rim reduced by the contact length between the bead and rim seats respectively, at least equal to 0.02% of the maximum axial width of the carcass reinforcement.
Un nombre important de jantes et de pneumatiques pouvant être concernés par l'invention, le profil méridien de l'ensemble formé par l'armature de carcasse et les couches additionnelles, profil très étroitement lié au profil de l'armature de carcasse, sera, dans un bourrelet, avantageusement adapté au profil méridien de la jante sur lequel sera monté ledit bourrelet. Le profil méridien des nappes additionnelles ne diffère, en effet, du profil méridien de l'armature de carcasse que par la variation possible de la (des) couche(s) caoutchouteuse(s) de découplage, renforcées ou non, existante(s) entre les deux armatures, ce qui explique que les dits profils sont dits sensiblement parallèles. Le profil méridien de la deuxième couche additionnelle peut être strictement parallèle au profil d'armature de carcasse, une seule couche de caoutchouc d'épaisseur constante séparant les deux profils. Le profil méridien de la deuxième couche peut être sensiblement parallèle au profil d'armature de carcasse, une ou plusieurs nappes de la première couche additionnelle pouvant s'insérer radialement entre l'armature de carcasse et la deuxième couche additionnelle, alors que la(les) nappe(s) restantes de la première couche sont radialement à l'extérieur et axialement à l'intérieur de la deuxième couche additionnelle.As a large number of rims and tires may be concerned by the invention, the meridian profile of the assembly formed by the carcass reinforcement and the additional layers, a profile very closely linked to the profile of the carcass reinforcement, will be, in a bead, advantageously adapted to the meridian profile of the rim on which said bead will be mounted. The meridian profile of the additional plies differs, in fact, from the meridian profile of the carcass reinforcement only by the possible variation of the rubber layer (s) of decoupling, reinforced or not, existing (s) between the two frames, which explains why the said profiles are said to be substantially parallel. The meridian profile of the second additional layer may be strictly parallel to the carcass reinforcement profile, a single layer of rubber of constant thickness separating the two profiles. The meridian profile of the second layer may be substantially parallel to the carcass reinforcement profile, one or more plies of the first additional layer being able to be inserted radially between the carcass reinforcement and the second additional layer, while the ) remaining ply (s) of the first layer are radially outside and axially inside the second additional layer.
Ledit profil méridien d'armature de carcasse dans un bourrelet peut être formé, en allant radialement et axialement vers l'intérieur, éventuellement d'un premier arc de cercle concave prolongé tangentiellement par un deuxième arc de cercle convexe, ledit deuxième arc de cercle étant éventuellement prolongé tangentiellement par un segment de droite.Said carcass reinforcement meridian profile in a bead can be formed, going radially and axially inwards, possibly with a first concave arc of a circle extended tangentially by a second convex arc of circle, said second arc of circle being possibly extended tangentially by a line segment.
L'extrémité radialement extérieure du premier arc de cercle concave est d'une part radialement distante de l'axe de rotation d'une quantité égale au rayon du cercle lieu géométrique des points du rebord de jante les plus éloignés dudit axe, et d'autre part axialement distante du plan équatorial d'une quantité comprise entre L + 0,1 L et L - 0,1 L. Ladite extrémité radialement extérieure est aussi le point de tangence avec le profil méridien convexe de l'armature de carcasse dans le flanc. Le centre de courbure du premier arc de cercle a, par rapport aux deux axes que sont la trace du plan équatorial et l'axe de rotation, les mêmes coordonnées que le centre de courbure du crochet de jante. Quant à la longueur dudit premier arc de cercle de profil d'armature de carcasse, elle au minimum nulle, le profil méridien d'armature de carcasse dans le bourrelet commençant directement par le deuxième arc de cercle convexe, et au maximum égale à la longueur d'un arc de cercle dont l'extrémité radialement inférieure serait le point de tangence dudit arc avec une perpendiculaire à l'axe de rotation.The radially outer end of the first concave arc is on the one hand radially distant from the axis of rotation by an amount equal to the radius of the circle at the geometrical location of the points of the rim flange furthest from said axis, and on the other hand axially distant from the equatorial plane by an amount between L + 0.1 L and L - 0.1 L. Said radially outer end is also the point of tangency with the convex meridian profile of the carcass reinforcement in the flank. The center of curvature of the first arc has, with respect to the two axes that are the trace of the equatorial plane and the axis of rotation, the same coordinates than the center of curvature of the rim hook. As for the length of said first arc of a carcass reinforcement profile, it is at least zero, the meridian profile of carcass reinforcement in the bead starting directly with the second convex arc, and at most equal to the length an arc of a circle whose radially lower end would be the point of tangency of said arc with a perpendicular to the axis of rotation.
Ledit premier arc de cercle est tangentiellement prolongé radialement et axialement à l'intérieur par un deuxième arc de cercle de rayon de courbure pouvant être compris entre une valeur minimale de 5 mm et une valeur maximale égale au rayon de courbure du profil méridien d'armature de carcasse dans le flanc mesuré au point de tangence entre ledit profil et le premier arc de cercle, ladite valeur maximale étant la valeur de rayon utilisée préférentiellement lorsque le premier arc de cercle a une longueur nulle.Said first arc of a circle is tangentially extended radially and axially inside by a second arc of a circle with a radius of curvature which can be between a minimum value of 5 mm and a maximum value equal to the radius of curvature of the meridian profile of reinforcement carcass in the sidewall measured at the point of tangency between said profile and the first arc, said maximum value being the value of radius preferably used when the first arc has a zero length.
Le deuxième arc de cercle est éventuellement tangentiellement prolongé radialement et axialement à l'intérieur par un segment de droite, dont l'extrémité axialement intérieure est aussi l'extrémité du profil méridien d'armature de carcasse. Le bord axialement intérieur du profil méridien est composé soit d'une partie du deuxième arc de cercle à laquelle s'ajoute le segment de droite, soit d'une partie d'arc de cercle. Ledit bord est la partie de profil méridien localisée dans un angle définie par une demi-droite tangente au deuxième arc de cercle et faisant avec l'axe de rotation un angle de 25° et une demi-droite parallèle audit axe de rotation dont l'origine est précisément le point de tangence du deuxième arc de cercle avec la demi-droite orientée à 25°. La première couche additionnelle a une extrémité axialement intérieure pouvant être plus proche ou plus éloignée du plan équatorial que l'extrémité axialement intérieure de l'armature de carcasse. Entre son extrémité axialement intérieure et le sommet de l'angle dans lequel est localisé le bord du profil méridien de l'armature de carcasse, la première couche additionnelle peut être séparée de la deuxième couche additionnelle par une faible épaisseur de mélange caoutchouteux, somme des deux épaisseurs respectives des couches de calandrage des deux nappes adjacentes, alors qu'entre ledit sommet et l'extrémité radialement supérieure, ladite épaisseur est comprise entre 1 ,0 et 1 ,8 fois l'épaisseur citée précédemment. Quant à la deuxième couche additionnelle, son extrémité axialement intérieure est distante axialement du plan équatorial d'une quantité sensiblement égale à la distance axiale séparant l'extrémité axialement intérieure de l'armature de carcasse dans le bourrelet. Entre ses extrémités radialement supérieure et axialement intérieure, ladite deuxième couche additionnelle est avantageusement séparée de l'armature de carcasse et/ou de la première couche additionnelle par une épaisseur qui est la somme des deux épaisseurs des couches de calandrage des couches adjacentes.The second arc of a circle is optionally tangentially extended radially and axially inside by a straight line segment, the axially inner end of which is also the end of the meridian profile of the carcass reinforcement. The axially inner edge of the meridian profile is composed either of a part of the second arc of a circle to which the line segment is added, or of a part of an arc of a circle. Said edge is the part of the meridian profile located at an angle defined by a half-line tangent to the second arc of a circle and making with the axis of rotation an angle of 25 ° and a half-line parallel to said axis of rotation, the origin is precisely the point of tangency of the second arc of a circle with the half-line oriented at 25 °. The first additional layer has an axially inner end which may be closer or further away from the equatorial plane than the axially inner end of the carcass reinforcement. Between its axially inner end and the apex of the angle in which the edge of the meridian profile of the carcass reinforcement is located, the first additional layer can be separated from the second additional layer by a small thickness of rubber mixture, sum of the two respective thicknesses of the calendering layers of the two adjacent plies, while between said apex and the radially upper end, said thickness is between 1.0 and 1.8 times the thickness mentioned above. As for the second additional layer, its axially inner end is axially distant from the equatorial plane by an amount substantially equal to the axial distance separating the axially inner end of the carcass reinforcement in the bead. Between its radially upper and axially inner ends, said second additional layer is advantageously separated from the carcass reinforcement and / or from the first additional layer by a thickness which is the sum of the two thicknesses of the calendering layers of the adjacent layers.
Dans le cas d'une pression de gonflage élevée, la présence d'une troisième couche additionnelle continue de renforcement peut aussi s'avérer très avantageuse. Ladite troisième couche, axialement à l'extérieur et radialement à l'intérieur d'au moins la nappe radialement la plus intérieure et axialement la plus extérieure de l'armature de carcasse, a aussi un profil méridien sensiblement parallèle au profil méridien de ladite armature de carcasse dans le bourrelet. Ladite couche est formée d'au moins une nappe d'éléments de renforcement. Elle peut être continue et homogène sur toute sa longueur depuis son extrémité radialement supérieure pouvant être située radialement à l'extérieur, mais de préférence radialement à l'intérieur, de la droite parallèle à l'axe de rotation de la jante et passant par le point du rebord de jante, correspondant au bourrelet considéré, le plus éloigné de l'axe de rotation, jusqu'à son extrémité axialement intérieure et la plus proche du plan équatorial. Elle est alors avantageusement formée de câbles inextensibles, de préférence métalliques, et faisant avec la direction circonférentielle un angle compris entre - 2,5° et + 2,5°.In the case of a high inflation pressure, the presence of a third additional continuous reinforcement layer can also prove to be very advantageous. Said third layer, axially outside and radially inside at least the radially innermost and axially outermost ply of the carcass reinforcement, also has a meridian profile substantially parallel to the meridian profile of said reinforcement carcass in the bead. Said layer is formed of at least one ply of reinforcing elements. It can be continuous and homogeneous over its entire length from its radially upper end which can be located radially outside, but preferably radially inside, from the straight line parallel to the axis of rotation of the rim and passing through the point of the rim flange, corresponding to the bead considered, the furthest from the axis of rotation, up to its axially inner end and closest to the equatorial plane. It is then advantageously formed of inextensible cables, preferably metallic, and making with the circumferential direction an angle between - 2.5 ° and + 2.5 °.
Dans le cas où son extrémité radialement supérieure est radialement à l'intérieur de la droite parallèle à l'axe de rotation et passant par le point du rebord de jante le plus éloigné dudit axe de rotation, ladite troisième couche additionnelle peut être aussi non homogène sur sa largeur bien que continue, et elle est alors avantageusement formée de deux parties : une première partie comprise entre son extrémité radialement supérieure et un point situé entre le milieu du deuxième arc de cercle du profil méridien d'armature de carcasse dans le bourrelet et le sommet de l'angle α dans lequel est située le bord d'armature de carcasse, et une deuxième partie, prolongeant axialement à l'intérieur et radialement à l'intérieur la première partie et comprise entre ledit point et son extrémité radialement inférieure et axialement la plus proche du plan équatorial. La première partie est formée d'au moins une nappe de câbles inextensibles, de préférence métalliques en acier, et faisant avec la direction circonférentielle un angle compris entre - 2,5° et + 2,5°, alors que la deuxième partie est avantageusement formée d'au moins une nappe d'éléments de renforcement, ladite nappe présentant les propriétés d'être très peu compressible dans le sens transversal et avantageusement extensible dans le sens circonférentiel, ce qui, d'une part, permet la maîtrise simple et reproductible des pressions exercées par le siège de bourrelet sur le siège de jante, les inventeurs ayant constaté de manière inattendue que lesdites pressions étaient fonction de la résistance à la tension des éléments de renforcement constituant la (les) nappe(s) de la deuxième partie de la deuxième couche additionnelle, et d'autre part, facilite la pose en fabrication de ladite couche additionnelle. Ladite deuxième partie peut être avantageusement formée d'au moins une nappe :In the case where its radially upper end is radially inside the straight line parallel to the axis of rotation and passing through the point of the rim flange furthest from said axis of rotation, said third additional layer may also be non-homogeneous over its width although continuous, and it is then advantageously formed of two parts: a first part lying between its radially upper end and a point situated between the middle of the second arc of a circle of the meridian profile of carcass reinforcement in the bead and the apex of the angle α in which the carcass reinforcement edge is situated, and a second part, extending axially inside and radially inside the first part and lying between said point and its radially lower end and axially closest to the equatorial plane. The first part is formed of at least one ply of inextensible cables, preferably metallic in steel, and forming with the circumferential direction an angle between - 2.5 ° and + 2.5 °, while the second part is advantageously formed of at least one ply of reinforcing elements, said ply having the properties of being very slightly compressible in the transverse direction and advantageously extensible in the circumferential direction, which, on the one hand, allows simple and reproducible control pressures exerted by the bead seat on the rim seat, the inventors having unexpectedly found that said pressures were a function of the tensile strength of the reinforcing elements constituting the ply (s) of the second part of the second additional layer, and on the other hand, facilitates the laying in manufacturing of said additional layer. Said second part may advantageously be formed from at least one ply:
* soit d'éléments de renforcement continus et circonférentiels, de préférence métalliques et dits élastiques, c'est-à-dire ayant sous une force de tension égal à 20 % de la force de rupture un allongement relatif au moins égal à 1,5 %,* either of continuous and circumferential reinforcing elements, preferably metallic and so-called elastic, that is to say having under a tensile force equal to 20% of the breaking force a relative elongation at least equal to 1.5 %,
* soit d'éléments de renforcement ondulés ou en zigzag d'orientation moyenne circonférentielle, et de préférence métalliques,* either corrugated or zigzag reinforcing elements of circumferential average orientation, and preferably metallic,
* soit de rangées d'éléments de renforcement préférentiellement métalliques, discontinus et circonférentiels, chaque élément ayant une longueur circonférentielle pouvant être comprise entre 0,1 fois et 1 fois la longueur circonférentielle de la nappe et les espaces entre éléments étant décalés méridiennement par rapport aux espaces des rangées axialement adjacentes et lesdits éléments ou rangées d'éléments étant cependant dans ce cas parallèles entre eux et pratiquement jointifs dans le sens transversal,* either of rows of preferably metallic reinforcing elements, discontinuous and circumferential, each element having a circumferential length which can be between 0.1 times and 1 time the circumferential length of the ply and the spaces between elements being offset meridally with respect to spaces of the axially adjacent rows and said elements or rows of elements being however in this case parallel to each other and practically contiguous in the transverse direction,
* soit d'éléments de renforcement métalliques orientés par rapport à la direction circonférentielle d'un angle au moins égal à 80°, lesdits éléments étant circonférentiellement séparés entre eux par une distance au moins égale à 0,2 mm.* or of metallic reinforcing elements oriented relative to the circumferential direction by an angle at least equal to 80 °, said elements being circumferentially separated from each other by a distance at least equal to 0.2 mm.
En outre, la pose de la deuxième partie de la deuxième couche peut être encore facilitée si la (les) nappe(s) de ladite partie sont formées de bandes de quelques éléments de renforcement circonférentiels, bandes discontinues circonférentiellement, les espaces de discontinuité entre bandes faisant avec la direction circonférentielle un angle différent de l'angle fait avec la même direction par les éléments de renforcement d'armature de carcasse, la différence étant au moins égale à 10°.In addition, the laying of the second part of the second layer can be further facilitated if the ply (s) of said part are formed from strips of a few circumferential reinforcing elements, circumferentially discontinuous strips, the spaces of discontinuity between strips doing with the circumferential direction an angle different from the angle made with the same direction by the carcass reinforcement reinforcing elements, the difference being at least equal to 10 °.
La position de la troisième couche et des nappes qui la composent peut être fonction du nombre de nappes composant l'armature de carcasse du pneumatique. Si ladite armature de carcasse est formée d'au plus trois nappes, la troisième couche additionnelle est préférentiellement en totalité située axialement à l'extérieur et radialement à l'intérieur de la nappe de carcasse radialement la plus à l'intérieur et axialement la plus à l'extérieur de l'armature de carcasse . Par contre, si ladite armature de carcasse est formée d'au moins quatre nappes, les nappes qui forment la troisième couche additionnelle sont préférentiellement telles que deux d'entre elles enserrent un groupe de nappes de carcasse pouvant être formé de une ou plusieurs nappes d'armature de carcasse.The position of the third layer and of the plies which compose it can be a function of the number of plies making up the carcass reinforcement of the tire. If said carcass reinforcement is formed of at most three plies, the third additional layer is preferably entirely located axially outside and radially inside the carcass ply radially innermost and axially most outside the carcass reinforcement. On the other hand, if said carcass reinforcement is formed of at least four plies, the plies which form the third additional layer are preferably such that two of them enclose a group of carcass plies which can be formed of one or more plies of carcass reinforcement.
Les caractéristiques et avantages de la présente invention seront mieux comprises à l'aide de la description qui suit et qui se réfère au dessin, sur lequel la figure unique représente schématiquement, vu en section méridienne, un bourrelet de pneumatique pour "Poids-Lourds".The characteristics and advantages of the present invention will be better understood with the aid of the description which follows and which refers to the drawing, in which the single figure represents schematically, seen in meridian section, a bead of tire for "Heavy goods vehicles" .
Le pneumatique "Poids-Lourds" de dimension 385/65 R 22.5 (figure 1), destiné à être monté sur une jante à base creuse possédant des sièges de jante inclinés à 15°, comprend une bande de roulement réunie à deux bourrelets (3) par deux flancs (2). Une armature de carcasse, composée d'une seule nappe (1) de câbles métalliques radiaux en acier, renforce ledit pneumatique et est surmontée d'une armature de sommet (non montrée) formée d'au moins deux nappes de câbles métalliques en acier parallèles entre eux dans chaque nappe et croisés d'une nappe à la suivante en faisant avec la direction circonférentielle des angles compris entre 10° et 35°.The "Heavy Duty" tire of dimension 385/65 R 22.5 (FIG. 1), intended to be mounted on a rim with a hollow base having rim seats inclined at 15 °, comprises a tread joined to two beads (3 ) by two sides (2). A carcass reinforcement, composed of a single ply (1) of radial metallic steel cables, reinforces said tire and is surmounted by a crown reinforcement (not shown) formed by at least two plies of parallel metallic steel cables between them in each tablecloth and crossed a tablecloth to the next, making angles between 10 ° and 35 ° with the circumferential direction.
Le profil méridien de la fibre géométriquement moyenne de la nappe de carcasse (1), vue en section méridienne, ledit profil étant considéré radialement à l'intérieur d'une droite XX' parallèle à l'axe de rotation de la jante de montage et du pneumatique passant par le point du rebord de jante, correspondant au bourrelet considéré, le plus éloigné de l'axe de rotation, est constitué par un premier arc de cercle concave AB. tangent en A au profil méridien de l'armature de carcasse dans le flanc (2) et en B à un deuxième arc de cercle convexe BC, lui même prolongé tangentiellement et axialement vers l'intérieur par un segment de droite CD faisant avec l'axe de rotation un angle de 20°, et D étant l'extrémité de l'armature de carcasse (1). Le point A est distant du plan équatorial d'une quantité égale à 149 mm, soit 0,5 fois la largeur L déjante 11.75 sur laquelle sera monté le pneumatique, alors que le point D est distant du même plan d'une quantité égale à 0,3 fois la même largeur dé jante. L'arc de cercle AB, comme on peut le voir sur la figure, n'a pas, du fait de la forme particulière du profil méridien du rebord de la jante à sièges 15°, la longueur maximale possible, le point B n'étant pas point de tangence avec une droite perpendiculaire à l'axe de rotation. Ledit profil méridien est donc courbé en allant axialement et radialement de l'extérieur à l'intérieur pour former un bord SD axialement intérieur, localisé dans un angle α ouvert axialement et radialement vers l'intérieur, dont l'un des côtés, faisant avec l'axe de rotation un angle de 25°, est tangent au deuxième arc de cercle BC en S, et dont l'autre côté partant de S est parallèle audit axe de rotation.The meridian profile of the geometrically medium fiber of the carcass ply (1), seen in meridian section, said profile being considered radially inside a straight line XX 'parallel to the axis of rotation of the mounting rim and the tire passing through the point of the rim flange, corresponding to the bead considered, the furthest from the axis of rotation, is constituted by a first concave arc AB. tangent in A to the meridian profile of the carcass reinforcement in the sidewall (2) and in B to a second arc of a convex circle BC, itself extended tangentially and axially inwards by a straight line CD making with the axis of rotation an angle of 20 °, and D being the end of the carcass reinforcement (1). Point A is distant from the equatorial plane by an amount equal to 149 mm, i.e. 0.5 times the width L already 11.75 on which the tire will be mounted, while point D is distant from the same plane by an amount equal to 0.3 times the same rim width. The arc of a circle AB, as can be seen in the figure, does not, due to the particular shape of the meridian profile of the flange of the rim with seats 15 °, the maximum possible length, point B n ' not being a point of tangency with a straight line perpendicular to the axis of rotation. Said meridian profile is therefore curved going axially and radially from the outside to the inside to form an axially inner SD edge, located in an angle α open axially and radially inwards, one of the sides of which forms with the axis of rotation an angle of 25 °, is tangent to the second arc of a circle BC in S, and the other side of which starting from S is parallel to said axis of rotation.
La première couche additionnelle (6) radialement extérieure et axialement intérieure est composée de trois nappes (6^ , (62) et (63) de câbles métalliques en acier 68x23 orientés circonférentiellement et dont la force de rupture est au moins égale à 700 daN. Les extrémités radialement inférieures des trois nappes sont plus éloignées du plan équatorial que l'extrémité de la nappe de carcasse et les extrémités radialement supérieures radialement étagées sont radialement à l'intérieur de la droite XX', à l'exception de la nappe (6j) la plus proche de la nappe de carcasse (1).The first additional radially outer and axially inner layer (6) is composed of three plies (6 ^, (6 2 ) and (6 3 ) of metallic steel cables 68x23 circumferentially oriented and whose breaking force is at least equal to 700 daN. The radially lower ends of the three plies are further from the equatorial plane than the end of the carcass ply and the radially upper ends radially stepped are radially inside the line XX ', with the exception of the ply (6j ) closest to the carcass ply (1).
Entre la dite nappe de carcasse (1) et la nappe additionnelle (6j) de la première couche additionnelle (6) est disposée une deuxième couche additionnelle (7) constituée d'une seule nappe (7), dans l'exemple décrit, de câbles métalliques en acier 19x18 orientés radialement. L'extrémité radialement supérieure de ladite nappe (7) est située radialement largement au-dessus de la droite XX' pour être située approximativement entre ladite droite et la droite de plus grande largeur axiale de l'armature de carcasse (1). Quant à l'extrémité axialement intérieure, elle est située à une distance axiale du plan équatorial égale à la distance axiale séparant dudit plan l'extrémité de la nappe de carcasse (1). La nappe additionnelle (6 est découplée de la deuxième couche additionnelle (7) par une mince couche de mélange caoutchouteux (8) dont l'épaisseur est égale à la somme des deux épaisseurs de mélange de calandrage recouvrant respectivement les câbles des dites nappes additionnelles, et dans le cas décrit égale à 0,6 mm. Il en est de même de la séparation entre la deuxième couche additionnelle (7) et l'armature de carcasse (1), découplées entre elle par la gomme (8) d'épaisseur égale à 1 ,2 mm.Between said carcass ply (1) and the additional ply (6j) of the first additional layer (6) is disposed a second additional layer (7) consisting of a single ply (7), in the example described, of 19x18 steel wire cables oriented radially. The radially upper end of said ply (7) is located radially largely above the line XX 'to be located approximately between said line and the line of greatest axial width of the carcass reinforcement (1). As for the axially inner end, it is located at an axial distance from the equatorial plane equal to the axial distance separating from said plane the end of the carcass ply (1). The additional ply (6 is decoupled from the second additional layer (7) by a thin layer of rubber mixture (8) whose thickness is equal to the sum of the two thicknesses of calendering mixture respectively covering the cables of said additional plies, and in the case described equal to 0.6 mm. It is the same for the separation between the second additional layer (7) and the carcass reinforcement (1), decoupled from one another by the thick rubber (8) equal to 1.2 mm.
La troisième couche additionnelle (9) est formée de deux parties :The third additional layer (9) is made up of two parts:
* d'une première partie (90), s'étendant du point A jusqu'à un point E du profil méridien d'armature de carcasse, sensiblement à égale distance des points C et S dudit profil, et formée d'une nappe de câbles métalliques 68x23 en acier, inextensibles, orientés circonférentiellement, et de diamètre égal à 2,8 mm et,* a first part (90), extending from point A to point E of the meridian profile of the carcass reinforcement, substantially equidistant from points C and S of said profile, and formed of a sheet of metal cables 68 × 23 in steel, inextensible, circumferentially oriented, and of diameter equal to 2.8 mm and,
* axialement à l'intérieur à partir dudit point E d'une deuxième partie (91 ) formée d'une nappe de câbles métalliques en acier ondulés dans le plan de la nappe et d'orientation moyenne circonférentielle et avec un rapport a/λ d'amplitude d'ondulation a sur la longueur d'ondes λ compris entre 0,03 et 0,1, les dits câbles en acier étant de plus petit diamètre que celui des câbles de la première partie (90), puisqu'égal à 1,4 mm.* axially inside from said point E of a second part (91) formed of a ply of metallic steel cables corrugated in the plane of the ply and of circumferential mean orientation and with a ratio a / λ d ripple amplitude a over the wavelength λ between 0.03 and 0.1, the said steel cables being of smaller diameter than that of the cables of the first part (90), since equal to 1 , 4 mm.
L'ensemble des nappes est recouvert dans le bourrelet et radialement à l'extérieur de la couche caoutchouteuse usuelle de protection (5) destinée à établir le contact avec la jante de montage et éventuellement du mélange constituant le flanc (2) du pneumatique. Quelle que soit la disposition ou l'arrangement de ces mélanges dans le bourrelet, l'épaisseur e de caoutchouc entre la fibre moyenne de la nappe de carcasse ( 1 ) et la paroi externe du bourrelet est, sur une longueur égale à la longueur totale de contact entre ladite paroi externe du bourrelet et la paroi interne de la jante de montage, diminuée de la longueur commune des sièges respectivement de bourrelet et de jante, égale à 13 mm, c'est-à-dire au moins égale à 0,034 % de la largeur axiale maximale de l'armature de carcasse (1). La longueur considérée correspond sensiblement à la longueur AS du profil méridien d'armature de carcasse (1). L'ensemble du bourrelet est complétée par un(des) bourrages de caoutchouc (4) axialement à l'intérieur et radialement à l'extérieur de la couche additionnelle (6). All of the plies are covered in the bead and radially outside the usual rubbery protective layer (5) intended to establish contact with the mounting rim and possibly with the mixture constituting the sidewall (2) of the tire. Whatever the arrangement or arrangement of these mixtures in the bead, the thickness e of rubber between the average fiber of the carcass ply (1) and the external wall of the bead is, over a length equal to the total length of contact between said external wall of the bead and the internal wall of the mounting rim, reduced by the common length of the bead and rim seats respectively, equal to 13 mm, that is to say at least equal to 0.034% the maximum axial width of the carcass reinforcement (1). The length considered corresponds substantially to the length AS of the meridian profile of the carcass reinforcement (1). The entire bead is completed by one (or more) rubber fillings (4) axially inside and radially outside the additional layer (6).

Claims

REVENDICATIONS
Pneumatique, destiné à être monté sur une jante dont les sièges font avec l'axe de rotation un angle γ tel que 0° < γ < 16°, et dont les rebords de jante ont des crochets arrondis, comprenant une bande de roulement réunie à deux bourrelets (3) par deux flancs (2) et au moins une armature de carcasse (1) formée d'au moins une nappe d'éléments de renforcement, caractérisé en ce que chaque bourrelet (3) est dépourvu de tringle, ladite armature de carcasse (1) ayant dans chaque bourrelet (3) un profil méridien courbé en allant axialement et radialement de l'extérieur à l'intérieur pour former un bord axialement intérieur localisé dans un angle α ouvert axialement et radialement vers l'intérieur, dont l'un des côtés est parallèle à l'axe de rotation, et de valeur au plus égale à 25°, ladite armature de carcasse (1) étant dans chaque bourrelet (3) au moins radialement à l'extérieur et axialement à l'intérieur renforcée, d'une part par au moins une première couche additionnelle (6) continue, composée d'au moins une nappe (6\, 62, 63) formée d'éléments de renforcement inextensibles faisant avec la direction circonférentielle un angle compris entre - 2,5° et + 2,5°, et d'autre part par au moins une deuxième couche additionnelle (7) continue, composée d'au moins une nappe formée d'éléments de renforcement inextensibles et radiaux, les deux couches additionnelles ayant des profils méridiens sensiblement parallèles au profil méridien d'armature de carcasse dans le bourrelet et les extrémités radialement supérieures des dites première et deuxième couches additionnelles étant distantes de l'axe de rotation de quantités au moins égales respectivement à 0,96 fois et 1,20 fois la distance séparant dudit axe le point du rebord correspondant de la jante de montage le plus éloigné dudit axe de rotation. - Pneumatique selon la revendication 1, caractérisé en ce que l'épaisseur de caoutchouc, existante entre la fibre moyenne du profil méridien de l'armature de carcasse et la paroi externe du bourrelet, est, sur une longueur égale à la longueur de contact entre bourrelet et jante diminuée de la longueur commune entre sièges respectivement de bourrelet et de jante, au moins égale à 0,02 % de la largeur axiale maximale de l'armature de carcasse.Pneumatic, intended to be mounted on a rim whose seats make with the axis of rotation an angle γ such as 0 ° <γ <16 °, and whose rim flanges have rounded hooks, comprising a tread joined to two beads (3) by two sides (2) and at least one carcass reinforcement (1) formed of at least one ply of reinforcing elements, characterized in that each bead (3) is devoid of rod, said reinforcement carcass (1) having in each bead (3) a meridian profile curved going axially and radially from the outside to the inside to form an axially inner edge located at an angle α open axially and radially inward, of which one of the sides is parallel to the axis of rotation, and of value at most equal to 25 °, said carcass reinforcement (1) being in each bead (3) at least radially on the outside and axially on the reinforced interior, on the one hand by at least a first 1st continuous additional layer (6), composed of at least one ply (6 \, 62, 63) formed of inextensible reinforcing elements making with the circumferential direction an angle comprised between - 2.5 ° and + 2.5 ° , and on the other hand by at least a second additional continuous layer (7), composed of at least one ply formed of inextensible and radial reinforcing elements, the two additional layers having meridian profiles substantially parallel to the meridian profile of carcass reinforcement in the bead and the radially upper ends of said first and second additional layers being spaced from the axis of rotation by amounts at least equal to 0.96 times and 1.20 times respectively the distance separating from said axis the point of corresponding edge of the mounting rim furthest from said axis of rotation. - A tire according to claim 1, characterized in that the thickness of rubber, existing between the average fiber of the meridian profile of the carcass reinforcement and the external wall of the bead, is, over a length equal to the contact length between bead and rim reduced by the common length between the bead and rim seats respectively, at least equal to 0.02% of the maximum axial width of the carcass reinforcement.
- Pneumatique selon la revendication 2, caractérisé en ce que l'extrémité axialement intérieure de la deuxième nappe additionnelle est distante axialement du plan équatorial d'une quantité sensiblement égale à la distance axiale séparant l'extrémité axialement intérieure de l'armature de carcasse dans le bourrelet.- A tire according to claim 2, characterized in that the axially inner end of the second additional ply is axially distant from the equatorial plane by an amount substantially equal to the axial distance separating the axially inner end of the carcass reinforcement in the bead.
- Pneumatique selon la revendication 3, caractérisé en ce que le profil méridien d'armature de carcasse (1) dans un bourrelet (3) est formé, en allant radialement et axialement vers l'intérieur, d'un premier arc de cercle AB concave prolongé tangentiellement en B par un deuxième arc de cercle convexe BC, ledit deuxième arc de cercle BC étant éventuellement prolongé tangentiellement par un segment de droite CD, D étant l'extrémité de l'armature de carcasse (1) dans le bourrelet (3).- A tire according to claim 3, characterized in that the meridian profile of the carcass reinforcement (1) in a bead (3) is formed, going radially and axially inward, of a first concave arc AB extended tangentially at B by a second convex arc BC, said second arc BC possibly being extended tangentially by a straight line CD, D being the end of the carcass reinforcement (1) in the bead (3) .
- Pneumatique selon la revendication 4, caractérisé en ce que l'extrémité radialement extérieure A du premier arc de cercle concave AB, point de tangence dudit arc AB avec le profil méridien convexe de l'armature de carcasse (1) dans le flanc (2), est d'une part radialement distante de l'axe de rotation d'une quantité égale au rayon du cercle, lieu géométrique des points du rebord de jante les plus éloignés dudit axe, et d'autre part axialement distante du plan équatorial d'une quantité comprise entre L + 0, 1 L et L - 0,1 L, le centre de courbure dudit arc AB ayant, par rapport aux deux axes que sont la trace du plan équatorial et l'axe de rotation, les mêmes coordonnées que le centre de courbure du crochet dé jante.- A tire according to claim 4, characterized in that the radially outer end A of the first arc of concave circle AB, point of tangency of said arc AB with the convex meridian profile of the carcass reinforcement (1) in the sidewall (2 ), is on the one hand radially distant from the axis of rotation by an amount equal to the radius of the circle, geometrical location of the points of the rim flange most distant from said axis, and on the other hand axially distant from the equatorial plane d 'an amount between L + 0, 1 L and L - 0.1 L, the center of curvature of said arc AB having, with respect to the two axes that are the trace of the equatorial plane and the axis of rotation, the same coordinates as the center of curvature of the rim hook.
- Pneumatique selon la revendication 4, caractérisé en ce que la longueur dudit premier arc de cercle AB de profil d'armature de carcasse est comprise entre une valeur nulle, le profil méridien d'armature de carcasse (1) dans le bourrelet (3) commençant directement par le deuxième arc de cercle BC convexe, et une valeur au maximum égale à la longueur d'un arc de cercle dont l'extrémité radialement inférieure B serait le point de tangence dudit arc avec une perpendiculaire à l'axe de rotation.- A tire according to claim 4, characterized in that the length of said first arc of a circle AB of carcass reinforcement profile is between a zero value, the meridian profile of carcass reinforcement (1) in the bead (3) starting directly with the second convex circular arc BC, and a value at most equal to the length of a circular arc whose radially lower end B would be the point of tangency of said arc with a perpendicular to the axis of rotation.
- Pneumatique selon l'une des revendications 4 à 6, caractérisé en ce que le deuxième arc de cercle BC, tangent en B au premier arc de cercle AB, a un rayon de courbure compris entre une valeur minimale de 5 mm et une valeur maximale égale au rayon de courbure du profil méridien d'armature de carcasse (1) dans le flanc (2) mesuré au point de tangence A entre ledit profil et le premier arc de cercle AB, ladite valeur maximale étant la valeur de rayon utilisée lorsque le premier arc de cercle AB a une longueur nulle.- A tire according to one of claims 4 to 6, characterized in that the second circular arc BC, tangent at B to the first circular arc AB, has a radius of curvature between a minimum value of 5 mm and a maximum value equal to the radius of curvature of the meridian profile of carcass reinforcement (1) in the sidewall (2) measured at the point of tangency A between said profile and the first arc AB, said maximum value being the value of radius used when the first arc of circle AB has zero length.
- Pneumatique selon l'une des revendications 4 à 7, caractérisé en ce que le bord axialement intérieur du profil méridien d'armature de carcasse, composé soit d'une partie du deuxième arc de cercle BC à laquelle s'ajoute le segment de droite CD, soit d'une partie d'arc de cercle BC, est la partie de profil méridien localisée dans un angle α défini par une demi-droite tangente en S au deuxième arc de cercle BC et faisant avec l'axe de rotation un angle de 25° et une demi-droite parallèle audit axe de rotation dont l'origine S est précisément le point de tangence du deuxième arc de cercle BC avec la demi-droite orientée à 25°.- Tire according to one of claims 4 to 7, characterized in that the axially inner edge of the meridian profile of the carcass reinforcement, composed either of a part of the second arc of a circle BC to which the line segment is added CD, either of a part of an arc of a circle BC, is the part of the meridian profile located in an angle α defined by a half-line tangent in S to the second arc of a circle BC and forming with the axis of rotation an angle of 25 ° and a half-line parallel to said axis of rotation whose origin S is precisely the point of tangency of the second arc of a circle BC with the half-line oriented at 25 °.
- Pneumatique selon les revendications 1 à 8, caractérisé en ce que la première couche additionnelle (6) est, entre son extrémité axialement intérieure et le sommet S de l'angle α dans lequel est localisé le bord de l'armature de carcasse (1), séparée de la deuxième couche additionnelle par une épaisseur minimale de mélange caoutchouteux, épaisseur qui est la somme des épaisseurs des couches de calandrage en regard respectivement des deux nappes adjacentes (1) et (61 ), alors qu'entre ledit sommet S et l'extrémité radialement supérieure, l'épaisseur de découplage est comprise entre 1,00 et 1,80 fois l'épaisseur minimale précédente.- A tire according to claims 1 to 8, characterized in that the first additional layer (6) is, between its axially inner end and the apex S of the angle α in which the edge of the carcass reinforcement (1 ), separated from the second additional layer by a minimum thickness of rubber mixture, thickness which is the sum of the thicknesses of the calendering layers opposite respectively of the two adjacent plies (1) and (61), while between said apex S and the radially upper end, the decoupling thickness is between 1.00 and 1.80 times the previous minimum thickness.
- Pneumatique selon la revendication 9, caractérisé en ce que la deuxième couche additionnelle (7) est, entre ses extrémités radialement supérieure et axialement intérieure, avantageusement séparée de l'armature de carcasse (1) et de la première couche additionnelle (6) par une faible épaisseur, qui est somme des deux épaisseurs des couches de calandrage des couches adjacentes.- A tire according to claim 9, characterized in that the second additional layer (7) is, between its radially upper and axially inner ends, advantageously separated from the carcass reinforcement (1) and from the first additional layer (6) by a small thickness, which is the sum of the two thicknesses of the calendering layers of the adjacent layers.
- Pneumatique selon l'une des revendications 1 à 10, caractérisé en ce que l'armature de carcasse (1) est renforcée, axialement à l'extérieur et radialement à l'intérieur d'au moins la nappe radialement la plus intérieure et axialement la plus extérieure de l'armature de carcasse (1), par une troisième couche additionnelle continue (9), formée d'au moins une nappe d'éléments de renforcement, ayant un profil méridien sensiblement parallèle au profil méridien de ladite armature de carcasse (1) dans le bourrelet (3), et composée d'éléments de renforcement inextensibles et circonférentiels.- Tire according to one of claims 1 to 10, characterized in that the carcass reinforcement (1) is reinforced, axially outside and radially inside at least the radially innermost ply and axially the outermost of the carcass reinforcement (1), by a third additional continuous layer (9), formed of at least one ply of reinforcing elements, having a meridian profile substantially parallel to the profile meridian of said carcass reinforcement (1) in the bead (3), and composed of inextensible and circumferential reinforcing elements.
- Pneumatique selon la revendication 1 1, caractérisé en ce que l'extrémité radialement supérieure de la couche additionnelle (9) est radialement à l'intérieur de la droite XX' parallèle à l'axe de rotation de la jante et passant par le point du crochet de jante, correspondant au bourrelet considéré, le plus éloigné dudit axe de rotation.- A tire according to claim 1 1, characterized in that the radially upper end of the additional layer (9) is radially inside the straight line XX 'parallel to the axis of rotation of the rim and passing through the point the rim hook, corresponding to the bead considered, the furthest from said axis of rotation.
- Pneumatique selon la revendication 12, caractérisé en ce que la troisième couche additionnelle (9) est de composition homogène et formée, dans son intégralité, de câbles inextensibles, de préférence métalliques, faisant avec la direction circonférentielle un angle compris entre - 2,5° et + 2,5°.- A tire according to claim 12, characterized in that the third additional layer (9) is of homogeneous composition and formed, in its entirety, of inextensible cables, preferably metallic, forming with the circumferential direction an angle between - 2.5 ° and + 2.5 °.
- Pneumatique selon la revendication 12, caractérisé en ce que la troisième couche additionnelle (9) est composée de deux parties, une première partie (90) comprise entre son extrémité radialement supérieure et un point situé approximativement entre le milieu de l'arc de cercle BC et le sommet S de l'angle α dans lequel est située le bord d'armature de carcasse (1), et une deuxième partie (91) comprise entre ledit point et son extrémité axialement intérieure, la première partie (90) étant formée d'au moins une nappe d'éléments de renforcement inextensibles et circonférentiels, alors que la deuxième partie (91) est formée d'au moins une nappe d'éléments de renforcement tels que ladite nappe présente les propriétés d'être peu compressible dans le sens transversal et extensible dans le sens circonférentiel. - Pneumatique selon la revendication 14, caractérisé en ce que les éléments de renforcement composant la deuxième partie (91) de la troisième couche additionnelle (9), sont des éléments de renforcement élastiques, continus, rectilignes et orientés circonférentiellement, lesdits éléments étant parallèles entre eux et pratiquement jointifs dans le sens transversal.- A tire according to claim 12, characterized in that the third additional layer (9) is composed of two parts, a first part (90) between its radially upper end and a point located approximately between the middle of the arc of a circle BC and the vertex S of the angle α in which the carcass reinforcement edge is located (1), and a second part (91) included between said point and its axially inner end, the first part (90) being formed at least one ply of inextensible and circumferential reinforcing elements, while the second part (91) is formed of at least one ply of reinforcing elements such that said ply has the properties of being not very compressible in the transverse and extendable in the circumferential direction. - A tire according to claim 14, characterized in that the reinforcing elements making up the second part (91) of the third additional layer (9) are elastic, continuous, rectilinear and circumferentially oriented reinforcing elements, said elements being parallel between them and practically joined in the transverse direction.
- Pneumatique selon la revendication 14, caractérisé en ce que les éléments de renforcement composant la deuxième partie (91) de la troisième couche additionnelle (9) sont des éléments de renforcement ondulés ou en zigzag dans le plan de nappe(s), d'orientation moyenne circonférentielle, avec un rapport d'amplitude d'ondulation a sur la longueur d'onde pouvant être compris entre 0,03 et 0,1, lesdits éléments étant parallèles entre eux et pratiquement jointifs dans le sens transversal.- A tire according to claim 14, characterized in that the reinforcing elements composing the second part (91) of the third additional layer (9) are corrugated or zigzag reinforcing elements in the plane of ply (s), d ' circumferential mean orientation, with a wavelength amplitude ratio a over the wavelength which may be between 0.03 and 0.1, said elements being parallel to each other and practically contiguous in the transverse direction.
- Pneumatique selon l'une des revendications 14, caractérisé en ce que la(les) nappe(s) composant la deuxième partie (91) de la troisième couche additionnelle (9) sont formées de rangées d'éléments de renforcement discontinus, chaque élément ayant une longueur circonférentielle pouvant être comprise entre 0,1 fois et 1 fois la longueur circonférentielle de la nappe qu'ils composent, et les espaces entre éléments étant décalés méridiennement par rapport aux espaces des rangées axialement adjacentes, lesdites rangées d'éléments étant parallèles entre elles et pratiquement jointives dans le sens transversal.- Tire according to one of claims 14, characterized in that the ply (s) making up the second part (91) of the third additional layer (9) are formed of rows of discontinuous reinforcing elements, each element having a circumferential length which may be between 0.1 times and 1 time the circumferential length of the ply which they compose, and the spaces between elements being offset meridally with respect to the spaces of the axially adjacent rows, said rows of elements being parallel between them and practically contiguous in the transverse direction.
- Pneumatique selon la revendication 14, caractérisé en ce que les éléments de renforcement composant la deuxième partie (91) de la troisième couche additionnelle (9) sont des éléments de renforcement métalliques orientés par rapport à la direction circonférentielle d'un angle au moins égal à 80°, lesdits éléments étant circonférentiellement séparés entre eux par une distance au moins égale à 0,2 mm.- A tire according to claim 14, characterized in that the reinforcing elements making up the second part (91) of the third additional layer (9) are metallic reinforcing elements oriented by with respect to the circumferential direction by an angle at least equal to 80 °, said elements being circumferentially separated from each other by a distance at least equal to 0.2 mm.
- Pneumatique selon la revendication 14, caractérisé en ce que la(les) nappe(s) de la deuxième partie (91) de la troisième couche additionnelle (9) sont formées de bandes de quelques éléments de renforcement circonférentiels, lesdites bandes étant circonférentiellement discontinus et les espaces de discontinuité entre bandes faisant avec la direction circonférentielle un angle différent de l'angle fait avec la même direction par les éléments de renforcement d'armature de carcasse, la différence étant au moins égale à 10°.- A tire according to claim 14, characterized in that the ply (s) of the second part (91) of the third additional layer (9) are formed from strips of a few circumferential reinforcing elements, said strips being circumferentially discontinuous and the spaces of discontinuity between bands making with the circumferential direction an angle different from the angle made with the same direction by the carcass reinforcement reinforcing elements, the difference being at least equal to 10 °.
- Pneumatique selon la revendication 11 , caractérisé en ce que l'armature de carcasse (1) est formée d'au plus trois nappes, la troisième couche additionnelle (9) étant en totalité située axialement à l'extérieur et radialement à l'intérieur de la nappe de carcasse radialement la plus à l'intérieur et axialement la plus à l'extérieur de l'armature de carcasse (1).- A tire according to claim 11, characterized in that the carcass reinforcement (1) is formed from at most three plies, the third additional layer (9) being entirely located axially outside and radially inside of the radially innermost and axially outermost carcass ply of the carcass reinforcement (1).
- Pneumatique selon la revendication 11, caractérisé en ce que l'armature de carcasse (1) est formée d'au moins quatre nappes, les nappes qui forment la troisième couche additionnelle (9) sont telles que deux d'entre elles enserrent un groupe de nappes de carcasse pouvant être formé de une ou plusieurs nappes d'armature de carcasse.- A tire according to claim 11, characterized in that the carcass reinforcement (1) is formed from at least four plies, the plies which form the third additional layer (9) are such that two of them enclose a group carcass plies which may be formed from one or more carcass reinforcement plies.
- Pneumatique selon l'une des revendications 1 à 21 , caractérisé en ce que l'armature de carcasse (1) est composée de nappes d'éléments de renforcement radiaux. - Tire according to one of claims 1 to 21, characterized in that the carcass reinforcement (1) is composed of plies of radial reinforcing elements.
EP00935005A 1999-05-25 2000-05-11 Coreless bead for tyre Expired - Lifetime EP1185426B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9906612 1999-05-25
FR9906612A FR2794064B1 (en) 1999-05-25 1999-05-25 PNEUMATIC TIRE-FREE BUCKLE
PCT/EP2000/004266 WO2000071366A1 (en) 1999-05-25 2000-05-11 Coreless bead for tyre

Publications (2)

Publication Number Publication Date
EP1185426A1 true EP1185426A1 (en) 2002-03-13
EP1185426B1 EP1185426B1 (en) 2004-01-28

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EP00935005A Expired - Lifetime EP1185426B1 (en) 1999-05-25 2000-05-11 Coreless bead for tyre

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US (1) US6598643B2 (en)
EP (1) EP1185426B1 (en)
JP (1) JP4580559B2 (en)
CN (1) CN100361831C (en)
AR (1) AR024095A1 (en)
AU (1) AU763199B2 (en)
BR (1) BR0010908A (en)
CA (1) CA2374502A1 (en)
DE (1) DE60007987T2 (en)
ES (1) ES2213017T3 (en)
FR (1) FR2794064B1 (en)
MX (1) MXPA01012007A (en)
RU (1) RU2244635C2 (en)
TR (1) TR200103382T2 (en)
WO (1) WO2000071366A1 (en)
ZA (1) ZA200002512B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002030688A1 (en) * 2000-10-10 2002-04-18 Societe De Technologie Michelin Tire having an outer carcass path
WO2003037659A1 (en) * 2001-10-31 2003-05-08 Pirelli Pneumatici S.P.A. Tyres for vehicle wheels with improved bead structure
JP5106846B2 (en) * 2003-01-17 2012-12-26 コンパニー ゼネラール デ エタブリッスマン ミシュラン Aircraft mounting assembly, wheels and tires
DE102011000703A1 (en) * 2011-02-14 2012-08-16 Continental Reifen Deutschland Gmbh Method for producing a pneumatic vehicle tire
CN115848070B (en) * 2023-02-23 2023-06-02 广饶县计量测试检定所(广饶县产品质量检验所、广饶县橡胶轮胎产品与材料质量检验中心) Tire ring part capable of improving ring part performance, tire and inspection method

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US3826297A (en) * 1972-10-26 1974-07-30 Steelastic Co Radial tire carcass
US3946785A (en) * 1974-08-01 1976-03-30 The Firestone Tire & Rubber Company Simplified bead construction for pneumatic tires
FR2715348A1 (en) * 1994-01-21 1995-07-28 Sedepro Anchoring the carcass of a tire.
FR2771050B1 (en) * 1997-11-14 1999-12-24 Michelin & Cie PNEUMATIC TIRE-FREE BUCKLE

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AU763199B2 (en) 2003-07-17
EP1185426B1 (en) 2004-01-28
AR024095A1 (en) 2002-09-04
MXPA01012007A (en) 2002-06-21
ZA200002512B (en) 2001-01-31
BR0010908A (en) 2002-03-05
AU5065500A (en) 2000-12-12
TR200103382T2 (en) 2002-04-22
JP4580559B2 (en) 2010-11-17
CN100361831C (en) 2008-01-16
RU2244635C2 (en) 2005-01-20
JP2003500271A (en) 2003-01-07
CA2374502A1 (en) 2000-11-30
FR2794064A1 (en) 2000-12-01
US6598643B2 (en) 2003-07-29
CN1351549A (en) 2002-05-29
FR2794064B1 (en) 2001-08-10
DE60007987D1 (en) 2004-03-04
US20020046792A1 (en) 2002-04-25
ES2213017T3 (en) 2004-08-16
DE60007987T2 (en) 2004-12-09
WO2000071366A1 (en) 2000-11-30

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